You already have it. It is the variable DISA valves from the 130i/330i/X5 3.0. It basically makes the 128i into a 130i.

I dont think this all.
Raceman mentioned that step 1 is to bump 125i to 130i 265hp, that's to tweak the valvetronic & disa of the 125i.
Step 2 is to tune that 265hp that more & use secondary cat delete exhaust.

I think DISA and AA only get us step 1
And any exhaust and intake max out at 10 hp total